Science: Watertight

In Boston one day last week officials of Provident Institution for
Savings watched the 30-ton door of their bank vault ponderously close
and lock. A motor compressor forced air into the vault through a
ventilator until a pressure-gauge climbed to 4 Ib. per square inch over
atmospheric pressure. At that level the gauge stood still nearly an
hour after the air input had stopped. A valve was then opened and the
compressed air wheezed out.

First of its kind that anyone knew of, the test showed the vault
airtight, hence watertight. With safety-deposit boxes only six inches
from the floor, the bank's...